The present invention relates to a motorcycle. More particularly, the present invention relates to a reverse drive assembly for a motorcycle.
Motorcycles commonly only include transmission assemblies operable to drive the motorcycles in a forward direction. If a user wishes to move the motorcycle in reverse, the user typically either has to walk the motorcycle backwards or dismount and push the motorcycle. However, such a task can be very difficult for smaller users or for a user trying to move a larger, heavier motorcycle (e.g., a trike). In addition, the user may also struggle when trying to move the motorcycle up a hill or over a curb in reverse.
A typical forward-driving transmission assembly 10 for a motorcycle is shown in FIGS. 1 and 2. The illustrated transmission assembly 10 includes a main shaft 14, a counter shaft 18, a set of first gears 22 coupled to the main shaft 14, and a set of second gears 26 coupled to the counter shaft 18. The main shaft 14, the counter shaft 18, and the gears 22, 26 are positioned within a transmission case 30 (FIG. 2) that is coupled to a frame of the motorcycle. The transmission assembly 10 is then coupled to an engine to drive the motorcycle in a forward direction.
The illustrated main shaft 14 includes an input end 34 configured to be rotated by the engine and an opposite end 38 supported by a support plate 42. The first gears 22 are integrally formed on the main shaft 14 to rotate with the main shaft 14. An output gear 46 is positioned around the input end 34 to transmit drive force from the transmission to a rear wheel of the motorcycle. As shown in FIG. 2, a bearing 50 is positioned between the output gear 46 and the main shaft 14 to allow relative rotation between the main shaft 14 and the output gear 46.
The illustrated counter shaft 18 extends parallel to the main shaft 14 and includes a first end 54 adjacent to the input end 34 of the main shaft 14 and a second end 58 opposite the first end 54. Each of the second gears 26 includes a bearing 62 positioned between the counter shaft 18 and the corresponding gear 26 to allow relative rotation between the counter shaft 18 and the gears 26. The second gears 26 are each in constant engagement with a corresponding first gear 22 such that the second gears 26 rotate whenever the main shaft 14 rotates. An output gear 66 is securely mounted near the first end 54 to rotate with the counter shaft 18. The output gear 66 of the counter shaft 18 intermeshes with the output gear 46 of the main shaft 14 to transmit rotation from the counter shaft 18 to the output gear 46 on the main shaft 14.
The illustrated transmission assembly 10 also includes a first dog ring 70 coupled to a first shifter fork 72 and a second dog ring 74 are coupled to a second shifter fork 76. The dog rings 70, 74 are slidably coupled to the counter shaft 18 to transmit rotation from the second gears 26 to the counter shaft 18. When a user selects a gear or shifts gears, the corresponding shifter fork 72, 76 moves the corresponding dog ring 70, 74 into engagement with a corresponding adjacent gear 26 such that the dog ring 70, 74 rotates with the gear 26 and transmits the rotation to the counter shaft 18. As shown in FIG. 1, a shifter drum 78 is coupled to the support plate 42 and to the shifter forks 72, 76 such that rotation of the shifter drum 78 moves the shifter forks 72, 76 to, in turn, move the dog rings 70, 74 when the user shifts gears.
Typically, the transmission assembly 10 also includes a side cover 82 (FIG. 2). The side cover 82 is coupled to the support plate 42 to cover a side opening 86 of the transmission case 30. The side opening 86 provides clearance for the opposite end 38 of the main shaft 14, the second end 58 of the counter shaft 18, and other components of the transmission assembly 10, in addition to providing maintenance access to the transmission assembly 10.
In operation, the engine rotates the main shaft 14, causing the first gears 22 and the second gears 26 to rotate. When the transmission is in neutral, the counter shaft 18 is not rotating and is, therefore, not transmitting rotation to the output gear 66. When a user selects a gear, one of the shifter forks 72, 76 slides the corresponding dog ring 70, 74 into engagement with the selected gear 26 on the counter shaft 18. Rotation is then transmitted from the main shaft 14, through the selected gears 22, 26 to the counter shaft 18 and through the output gear 66 on the counter shaft 18 to the output gear 46 on the main shaft 14. The output gear 46 transmits the rotation to the rear wheel of the motorcycle (e.g., through a chain, belt, or shaft drive) to thereby drive the motorcycle in the forward direction.